function C = non_windowed_est(x, p)
	[N,n] = size(x);
	H = zeros(N-p,0);
	for i=p+1:-1:1
		H = [H, x(i:N-p+i-1,:)];
	end
	H = H';
	C = 1/(N-p) * H * H';
end
